Fabry-Perot Interferometric Calibration of 2D Nanomechanical Plate Resonators

TL;DR

This paper introduces an in-situ optical calibration method for 2D nanomechanical plate resonators using Fabry-Perot interference, enabling precise measurement of physical parameters and displacement without external calibration.

Contribution

The study presents a novel Fabry-Perot based calibration scheme that accurately determines thickness, gap height, and displacement of nanomechanical resonators in-situ, applicable to various cavity configurations.

Findings

Calibration of resonator parameters achieved with high accuracy.

Displacement signals converted from optical contrast measurements.

Extraction of modal radius, effective mass, and Young's modulus.

Abstract

Displacement calibration of nanomechanical plate resonators presents a challenging task. Large nanomechanical resonator thickness reduces the amplitude of the resonator motion due to its increased spring constant and mass, and its unique reflectance. Here, we show that the plate thickness, resonator gap height, and motional amplitude of circular and elliptical drum resonators, can be determined in-situ by exploiting the fundamental interference phenomenon in Fabry-Perot cavities. The proposed calibration scheme uses optical contrasts to uncover thickness and spacer height profiles, and reuse the results to convert the photodetector signal to the displacement of drumheads that are electromotively driven in their linear regime. Calibrated frequency response and spatial mode maps enable extraction of the modal radius, effective mass, effective driving force, and Young's elastic modulus of the drumhead material. This scheme is applicable to any configuration of Fabry-Perot cavities, including plate and membrane resonators.